#include <iostream>
#include <string>
#include <cstdio>
#include <algorithm>

using namespace std;

int main()
{
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
    string s, s1;
    while (cin >> s1) {
        s += s1;
    }
    s1 = s;
    reverse(s.begin(), s.end());
    if (s == s1) {
        cout << "YES\n";
    } else {
        cout << "NO\n";
    }
    return 0;
}